1. Field of the Invention
PAN type carbon fibers and pitch type carbon fibers are in use mainly in the fields of the materials relating to space aircrafts, lubricating parts, cement-reinforcing material, and the like. If the cost of carbon fiber can be reduced in the future by the improvement in the production technique of carbon fiber, an advance into automobile-related materials will also be expectable.
It should be noted here that carbon filament or tow-like carbon fiber is cut into a certain length (for example, 1 to 25 mm) and the resulting chopped strand is put to use in most of the fields, except for the field of space aircraft -related materials.
Taking notice of this point, the present invention has been invented. Thus, the present invention relates to a process for easily producing an inexpensive carbon fiber chopped strand of high quality from pitch type carbon fiber difficult to handle which comprises cutting a pitch fiber to obtain a chopped strand just after spinning, followed by infusibilizing, carbonizing and graphitizing the chopped strand in a state of high density accumulation.
2. Brief Description of the Prior Art
Hitherto, carbon fiber chopped strands have been produced in the following manner: